TWI814872B - Temporary-fixing substrates, temporary-fixing method and a method of producing electronic parts - Google Patents

Abstract

The object of the present invention is to temporarily fix a substrate, which has a fixing surface for temporarily fixing a silicon substrate or the like, and a bottom surface on the opposite side of the fixing surface to reduce the time required for the temporarily fixing substrate to be attached to the silicon substrate. Then the amount of curvature of the body. The solution of the present invention is a temporarily fixed substrate 21, which is made of ceramic or glass and has: a fixing surface 21a for joining at least one of the silicon substrate and the electronic component wafer; and a bottom surface 21b on the opposite side of the fixing surface 21a. . The temporarily fixed substrate 21 has an outer peripheral flat plate portion 21c and a concave deformation portion 21d surrounded by the outer peripheral flat plate portion. The fixed surface 21a has a flat surface 21e on the outer peripheral flat surface.

Description

Temporarily fixed substrate, temporary fixing method, and manufacturing method of electronic component

The present invention relates to a temporarily fixed substrate, a temporarily fixed method of a silicon substrate, and a manufacturing method of an electronic component.

In recent years, the demand for miniaturization and low profile of electronic components has increased, and silicon substrates used in their manufacture are increasingly used in an extremely thin state. At this time, the thinned silicon substrate cannot withstand transportation and grinding due to insufficient rigidity. Grinding and other processes, it is known that a method is to use a temporarily fixed substrate composed of glass and ceramic to support the silicon substrate (Patent Documents 1, 2, and 3).

In these prior technologies, a silicon substrate is bonded to a temporarily fixed substrate by thermosetting resin, and after cooling, the silicon substrate is ground. Grinding and thinning. Next, multilayer wiring is further formed on the surface, and then the silicon substrate is peeled off from the temporarily fixed substrate and cut into a desired size. A peeling layer is provided on the adhesive layer in advance, and the silicon substrate is peeled off from the temporarily fixed substrate by irradiating the peeling layer with laser from the temporarily fixed substrate side.

When the silicon substrate is adhered to the temporarily fixed substrate with a thermosetting resin, the adhered body may be bent due to the difference in thermal expansion between the silicon substrate and the temporarily fixed substrate. Therefore, in Patent Document 2, an attempt is made to reduce the bending of the bonded body by bending the support substrate in advance in a direction opposite to the curvature of the bonded body. It supports the bending of the substrate and adjusts it by heating deformation, changing the grinding method, removing the processing-degraded layer, etc.

[Prior Technical Document]

〔Patent documents〕

[Patent Document 1] Japanese Patent Application Laid-Open No. 2011-023438

[Patent Document 2] Japanese Patent Application Laid-Open No. 2010-058989

However, due to conditions such as the type of thermosetting resin, bonding temperature, and the thickness of the temporarily fixed substrate and the silicon substrate, the amount of bending of the bonded body after bonding may become large. At this time, it may be necessary to make the initial bending amount of the temporarily fixed substrate to the opposite side larger depending on the bending amount of the bonded body. However, in such a case, during bonding, the operability of each substrate in the bonding equipment becomes difficult, or the substrates may be broken due to the pressure during bonding. Furthermore, after obtaining the bonded body, the silicon substrate is ground. When the thickness is reduced by grinding, the amount of bending of the bonded body will be close to the initial amount of bending of the temporarily fixed substrate before bonding to the silicon substrate. Therefore, the amount of bending becomes larger than the amount of bending of the bonded body immediately after bonding, making it difficult to implement subsequent processes.

The object of the present invention is to provide a temporarily fixed substrate, which has a fixing surface for temporarily fixing a silicon substrate and an electronic component wafer, and a bottom surface on the opposite side of the fixing surface to further reduce the difficulty in joining the temporarily fixed substrate. The amount of bending of the bonded body behind the silicon substrate or electronic component wafer.

The present invention is a temporarily fixed substrate, which is made of ceramics or glass and has: a fixed surface for joining at least one of a silicon substrate and an electronic component wafer; and a bottom surface on the opposite side of the fixed surface, and is characterized by: It has an outer peripheral flat plate portion; and a concave deformation portion surrounded by the outer peripheral flat plate portion, and the fixing surface is a flat surface on the outer peripheral flat plate portion.

In addition, the present invention is a temporary fixing method, characterized in that it includes: the step of: fixing the fixing surface of the temporarily fixing substrate; and obtaining a bonded body by following at least one of the silicon substrate and the electronic component wafer; and removing the silicon layer from the above-mentioned silicon substrate. Steps to temporarily secure substrate separation.

Furthermore, the method for manufacturing an electronic component according to the present invention is characterized by: having the step of bonding the silicon substrate to the fixed surface of the temporarily fixed substrate to obtain a bonded body; and providing an adhesive in or on the silicon layer. The steps of the electronic component wafer; and the step of separating the silicon layer and the electronic component wafer from the temporarily fixed substrate.

Furthermore, the present invention provides a method for manufacturing an electronic component, which includes the steps of: bonding the electronic component wafer to the fixing surface of the temporarily fixed substrate to obtain a bonded body; and separating the electronic component wafer from the temporarily fixed substrate. steps.

According to the present invention, the temporarily fixed substrate is made of ceramic and has a fixing surface for temporarily fixing at least one of the silicon substrate and the electronic component wafer; and a bottom surface on the opposite side of the fixing surface, even if it is temporarily The initial bending of the fixed substrate is the same, and the amount of bending of the bonded body after the silicon substrate and the electronic component wafer are bonded to the temporarily fixed substrate can be further reduced. As a result, there is no need to make the initial bending amount of the temporarily fixed substrate too large, and each substrate can be easily handled by the bonding equipment, and cracking due to pressure during bonding can be suppressed. In addition, after the bonded body is obtained, the silicon substrate is ground, for example. After grinding and thinning, the amount of bending of the bonded body can be reduced, and subsequent handling of the bonded body becomes easier.

First, a temporary fixing and separation method of a silicon substrate using a temporarily fixing substrate will be described with reference to FIGS. 1 and 2 . First, in the example shown in FIG. 1( a ), a predetermined conductor 3 is provided on the bonding surface 2 a side of the silicon substrate 2 . Then, the adhesive layer 4 and the peeling layer 5 are provided on the surface 2a of the silicon substrate 2. The joint surface 1 a of the temporarily fixed substrate 1 faces the surface 5 a of the release layer 5 .

Next, as shown in FIG. 1(b) , the silicon substrate 2 and the temporarily fixed substrate 1 are joined to obtain a bonded body. Next, the non-joining surface 2b of the silicon substrate 2 is processed to thin the silicon layer 2A as shown in FIG. 1(c). 2c is the processing surface. In this example, when the silicon layer 2A is thinned, the conductor 3A penetrates the silicon layer 2A.

Next, as shown in FIG. 2(a) , a predetermined wiring layer 6 is formed on the silicon substrate 2A. 7 is a rewiring layer for supplying power to the device wafer (electronic component wafer) provided on the wiring layer. Formed by engraving process or plating method. A plurality of wafers (not shown) are placed on the wiring layer as necessary, and then laser light with a predetermined wavelength and energy is irradiated from the temporarily fixed substrate side to cause peeling of the temporarily fixed substrate 1 in the peeling layer 5 . Thereby, as shown in FIG. 2(b) , the silicon layer 2A, together with the adhesive layer 4 and the wiring layer 6, are separated from the temporarily fixed substrate to provide the next processing step.

Here, when the silicon substrate is bonded to the temporarily fixed substrate with the thermosetting resin, the bonded body may be bent due to the difference in thermal expansion between the silicon substrate and the temporarily fixed substrate. Therefore, as shown in FIG. 3(a) , a method is known in which the temporarily fixed substrate 11 is bent in advance in a direction opposite to the bending of the bonded body. That is, the joint surface 11a of the temporarily fixed substrate 11 is dented, and the joint surface 11b is bulged. 12a is a joint surface, and 12b is a non-joint surface. Here, L is an imaginary surface when the temporarily fixed substrate 11 is not bent, and W is the amount of bending. However, when the joint surface is recessed, it is represented by a negative sign, and when the joint surface is protruded, it is represented by a positive sign.

Next, as shown in FIG. 3(b) , the temporarily fixed substrate 11 and the silicon substrate 12 are sandwiched between the jigs 13, and pressure and heating are applied as indicated by arrow A.

It is preferable that a thermosetting adhesive (not shown) is interposed between the temporarily fixed substrate 11 and the silicon substrate 12 and then hardened to connect the temporarily fixed substrate 11 and the silicon substrate 12 . At this point, by heating and pressing, both the temporarily fixed substrate 11 and the silicon substrate 12 are in a flat state.

When the bonding is completed, as shown in FIG. 3(c) , the bonded body 14 that temporarily fixes the substrate 11A and the silicon substrate 12A can be obtained. However, in the bonded body, the temporarily fixed substrate 11A is bent toward the opposite side from the initial stage. In this case, since the thermal expansion coefficient of the temporarily fixed substrate 11A is larger than that of silicon, it shrinks as indicated by the arrow mark B during cooling. As a result, the entire adhesive body 14 is bent toward the opposite side. The amount of bending W has a positive sign.

Next, as shown in FIG. 4(a) , the bonded body 14A is placed on the flat surface 15a of the jig 15, and pressure is applied as indicated by the arrow mark C to make the bonded body flat and processed. Thereby, the silicon substrate is thinned to form a thin silicon layer 12B, and at the same time, the silicon layer and the temporarily fixed substrate 11A are planarized. Next, when the bonding body 14A is removed from the jig 15, the bonding body 14A will bend again as shown in FIG. 4(b). However, the bending amount W of the bonding body 14A becomes smaller than the bending amount W before thin plate processing shown in FIG. 3(c), and is close to the bending of the temporarily fixed substrate before joining (FIG. 3(a)).

Next, as shown in FIG. 4(c) , the silicon layer is separated from the temporarily fixed substrate. At this time, the shape of the temporarily fixed substrate 11A tends to return to its initial shape. On the other hand, since the silicon layer has been thinned, it is generally flat.

Here, by setting the initial bending amount W of the temporarily fixed substrate 11 in FIG. 3(a) to a direction with a negative sign, the bending amount W of the bonded body 14 after joining shown in FIG. 3(c) can be made (positive sign opposite to the initial stage) becomes smaller. However, depending on conditions such as the type of thermosetting resin, bonding temperature, and the thickness of the temporarily fixed substrate and the silicon substrate, the amount of bending of the bonded body after bonding may become large (Fig. 3(c)). At this time, the initial bending amount of the temporarily fixed substrate required to the opposite side becomes larger depending on the bending amount of the bonded body (Fig. 3(a)). However, when doing so, during bonding as shown in Figure 3(b), the operation of the bonding equipment for each substrate may change. Difficulty in joining, or cracking due to pressure during joining. In addition, after obtaining the bonded body, the silicon substrate is ground. When thinned by polishing, the amount of bending of the bonded body will be close to the initial amount of bending of the temporarily fixed substrate before bonding to the silicon substrate (Fig. 4(b)). Therefore, the amount of bending becomes larger than the amount of bending of the bonded body immediately after bonding, making it difficult to implement subsequent processes.

Figures 5 to 8 relate to embodiments of the present invention.

FIG. 5(a) shows the material 20 for temporarily fixing the substrate. The thickness of the substrate material 20 (the distance between the pair of main surfaces 20a and 20b) is temporarily fixed to be constant.

Next, as shown in FIGS. 5(b) and (c) , the main surface 20a side of the material 20 is recessed and deformed to obtain the temporarily fixed substrate 21. Here, the thickness t21 of the temporarily fixed substrate 21 (the distance between the pair of main surfaces 21a and 21b) is fixed. An outer peripheral flat plate portion 21c is provided at the peripheral edge of the temporarily fixed substrate 21, and a concave deformation portion 21d is provided inside the temporarily fixed substrate 21. The outer peripheral flat plate portion 21c is formed into an annular flat plate shape and maintains the shape before processing shown in Fig. 5(a). L is an imaginary surface along the main surface 21a (flat surface 21e) of the outer peripheral flat plate portion 21c. On the other hand, the concave deformation portion 21d is deformed downward (the main surface 21b side) from the virtual surface L and is recessed. In this example, the planar shape of the concave deformation portion 21d is circular. The maximum value of the depression from the virtual surface L of the concave deformation portion 21b is defined as the bending amount W.

In the example shown in FIG. 6( a ), the bonding surface 22 a of the silicon substrate 22 and the bonding surface 21 a of the temporarily fixed substrate 21 are opposed to each other. Otherwise, a predetermined adhesive layer and a peeling layer can be further formed on the bonding surface 22a side of the silicon substrate 22. Next, as shown in FIG. 6( b ), the temporarily fixed substrate 21 and the silicon substrate 22 are sandwiched between the jigs 13 , and the side A marked by the arrow is heated under pressure. A thermosetting adhesive (not shown in the figure) is interposed between the temporarily fixed substrate 21 and the silicon substrate 22 and is cured to bond the temporarily fixed substrate 21 and the silicon substrate 22 . At this point, both the temporarily fixed substrate 21 and the silicon substrate 22 are in a flat state by applying heat and pressure.

When the bonding is completed, as shown in FIG. 6(c) , the bonded body 23 that temporarily fixes the substrate 21A and the silicon substrate 22 can be obtained. However, in the bonded body, the thermal expansion coefficient of the temporarily fixed substrate 21A is larger than that of silicon, so it shrinks as indicated by arrow B during cooling. As a result, the entire bonded body 23 bends toward the opposite side.

Next, as shown in FIG. 7(a) , the bonded body 23 is placed on the flat surface 15a of the jig 15, and pressure is applied as indicated by the arrow mark C to flatten the bonded body for processing. Thereby, the silicon substrate 22A is thinned to form the thin silicon layer 22B, and at the same time, the silicon layer and the temporarily fixed substrate are planarized. 22c is the processing surface. Then, when the bonding body 23A is removed from the jig 15, the bonding body 23A will bend again as shown in FIG. 7(b). However, temporarily fixing the substrate will bring it close to its initial shape. That is, the bending amount W of the bonding body 23A becomes smaller than the bending amount W before thin plate processing shown in FIG. 6(c) and is close to the shape of the temporarily fixed substrate before joining.

Next, as shown in FIG. 7(c) , the silicon layer 22B is separated from the temporarily fixed substrate. At this time, the shape of the temporarily fixed substrate 21 tends to return to its initial shape. On the other hand, since the silicon layer has been thinned, it is generally flat.

Here, in the present invention, as shown in Fig. 6(a), even if the initial bending amount of the temporarily fixed substrate is the same, when the temporarily fixed substrate is connected to the silicon substrate (see Fig. 6(b)), the outer peripheral flat plate portion 21c will not deformation, and only the concave deformation portion 21d is deformed flat by the jig 13. Then, the outer peripheral flat plate portion has an annular shape and surrounds the concave deformation portion, so it functions as an anchor to prevent the shape of the temporarily fixed substrate from being greatly deformed. As a result, the amount of bending after the bonded body 23 is removed from the jig 13 can be reduced (see FIG. 6(c) ).

As a result, even if the initial bending amount of the temporarily fixed substrate is the same, the bending amount after the bonding body 23 is removed from the jig 13 can be reduced. In addition, when the amount of bending after removing the bonding body 23 from the jig 13 is the same, the initial amount of bending of the temporarily fixed substrate can be reduced. Therefore, each substrate can be easily handled by the bonding equipment, and cracking due to pressure during bonding can be suppressed. In addition, after obtaining the bonded body, the silicon substrate is ground. After grinding and thinning (see FIG. 7( b )), the amount of curvature of the bonded body 23A can be reduced, and subsequent handling of the bonded body becomes easier.

Hereinafter, an embodiment using the temporarily fixed substrate of the present invention for bonding electronic component wafers will be described. First, the electronic component is attached to the above-mentioned fixing surface of the temporarily fixed substrate and temporarily fixed with a resin mold. For example, as shown in FIG. 9(a) , an adhesive layer is provided on the fixing surface 1a to which the substrate 1 is temporarily fixed. Examples of such adhesives include double-sided tape and hot-melt adhesives. In addition, as a method of providing the adhesive layer on the temporarily fixed substrate, various methods such as roller coating, spray coating, screen printing, and spin coating can be used.

Next, a plurality of electronic components 36 are placed on the temporarily fixed substrate 1, and the adhesive layer is hardened to form the adhesive layer 34. This hardening step is carried out according to the properties of the adhesive, but examples include heating and ultraviolet irradiation.

Next, a liquid resin molding agent is poured in and the resin molding agent is hardened. Thereby, as shown in FIG. 9(a) , the electronic component 36 is fixed in the resin mold 35 . However, 35b is a resin filling the gap 37 of the electronic component, and 35a is a resin covering the electronic component. Examples of the mold resin include epoxy resin, polyimide resin, polyurethane resin, urethane resin, and the like.

Next, as indicated by arrow A, the electronic component 36 and the resin mold 35 are separated from the temporarily fixed substrate 1 by irradiating light from the bottom surface 1b side of the temporarily fixed substrate 1 (see FIG. 9(b) ). The wavelength of the light irradiated from the bottom surface of the temporarily fixed substrate can be appropriately changed according to the type of the electronic component and the resin mold, but may be, for example, 200 nm to 400 nm.

Each component of the present invention will be further described below. The material of the temporarily fixed substrate is preferably ceramic in terms of mechanical strength and durability against chemicals, with aluminum oxide, aluminum nitride, YAG, silica aluminum oxynitride, and spinel being particularly preferred.

In a suitable embodiment, the material constituting the temporarily fixed substrate is translucent alumina. At this time, it is preferable to add 100 ppm or more and 300 ppm or less magnesium oxide powder to the high-purity alumina powder with a purity of 99.9% or more (preferably 99.95% or more). As such high-purity alumina powder, high-purity alumina powder manufactured by Daemyung Chemical Industry Co., Ltd. can be exemplified. In addition, the purity of the magnesium oxide powder is preferably 99.9% or more, and the average particle size is preferably 50 μm or less.

In addition, in a suitable embodiment, as sintering aids, it is preferable to add 200 to 800 ppm zirconium oxide (ZrO ₂ ) and 10 to 30 ppm yttrium trioxide (Y ₂ O ₃ ) to the alumina powder.

The method of forming the temporarily fixed substrate is not particularly limited, and may be any method such as a doctor blade method, an extrusion method, or a casting method. It is especially preferable to use the doctor blade method to manufacture the base substrate.

In a suitable embodiment, a slurry containing ceramic powder, a dispersant and a binder is produced, the slurry is formed into a thin strip using a doctor blade method, the layers are laminated into a desired thickness shape, and a formed body is obtained by punching.

Next, the formed body is dried, preferably fired in the air, and then fired in hydrogen gas. From the viewpoint of densification of the sintered body, the sintering temperature during firing is preferably 1700 to 1900°C, and more preferably 1750 to 1850°C. The surface of this sintered body is polished by diamond polishing or the like to adjust the thickness variation to a certain level or less, and make both surfaces mirror-finished.

In this way, after a sufficiently dense sintered body is generated during firing, the amount of bending can be adjusted with high accuracy by adjusting the thickness variation, mirroring the surface, and then performing an annealing treatment. From the viewpoint of preventing deformation or abnormal grain growth, the annealing temperature is preferably 1,700°C or lower, and the maximum temperature is more preferably 1,600°C or lower. On the other hand, in order to fully advance the creep deformation of the sintered body and adjust the bending amount with high accuracy, the temperature is preferably 1200°C or higher, and more preferably 1400°C or higher. In addition, the annealing time is preferably 1 to 6 hours.

In addition, the glass constituting the temporarily fixed substrate may be silicate glass or borosilicate glass.

The temporarily fixed substrate of the present invention has an outer peripheral flat plate portion; and a concave deformation portion surrounded by the outer peripheral flat plate portion, and the fixing surface is a flat surface on the outer peripheral flat plate portion. Here, the width F of the outer peripheral flat plate portion (see FIGS. 5(b) and (c) ) is preferably 4% or more of the width R of the temporarily fixed substrate 21 , thereby increasing the effect of suppressing the amount of bending of the bonded body. . From this point of view, the width F of the outer peripheral flat plate portion is more preferably 8% or more of the width R of the temporarily fixed substrate 21 , and particularly preferably 10% or more.

In addition, the width F of the outer peripheral flat plate portion is preferably 60% or less of the width R of the temporarily fixed substrate 21, so that the amount of bending of the bonded body can be suppressed to a greater extent. From this point of view, the width F of the outer peripheral flat plate portion is more preferably 40% or less of the width R of the temporarily fixed substrate 21 , and particularly preferably 30% or less.

Furthermore, the width R of the temporarily fixed substrate is the length of a line segment that crosses the temporarily fixed substrate in a plane. In addition, the width F of the outer peripheral flat plate portion is the total value of the length of the line segments crossing the outer peripheral flat plate portion among the above-mentioned line segments that cross the temporarily fixed substrate in a plane. For example, as shown in the plan view in FIG. 5(c) , the widths of the two outer peripheral flat plates temporarily fixed in the width direction of the substrate are respectively F/2. At this time, the width of the outer peripheral flat plate becomes (F/2 + F/2). =F.

In addition, depending on the direction of the line segment crossing the temporarily fixed substrate, the width R of the temporarily fixed substrate and the width F of the outer peripheral flat plate portion may change. For example, in the example shown in FIG. 8 , the planar shape of the temporarily fixed substrate 31 is rectangular, and the thickness of the temporarily fixed substrate 31 (the distance between the main surface 31 a and the opposite main surface) is fixed. An outer peripheral flat plate portion 31c is provided at the peripheral edge of the temporarily fixed substrate 31, and a concave deformation portion 31d is provided inside the outer peripheral flat plate portion 31c. The outer peripheral flat plate portion 31c has a flat plate shape, and the main surface 31a of the outer peripheral flat plate portion 31 constitutes a flat surface 31e. The concave deformation portion 31d is deformed downward from the imaginary surface and is recessed. In this example, the planar shape of the concave deformation portion 31d is rectangular. For example, when the planar shape of the temporarily fixed substrate is a rectangle, the longitudinal width R2 and the transverse width R1 are different, and the longitudinal outer peripheral flat plate width F2 (F2/2+F2/2) may be different from the transverse width R2. The width F1 (F1/2+F1/2) of the outer peripheral flat plate portion is different. At this time, the longitudinal and transverse directions (width of the outer peripheral flat plate part/width of the temporarily fixed substrate (F1/R1, F2/R2)) are preferably 4 to 60% respectively.

When the substrate is temporarily fixed before joining, the bending amount W of the concave deformation portion is preferably 0.1 mm or more, thereby suppressing the bending amount of the bonded body. From this point of view, the bending amount W of the concave deformation portion is more preferably 0.3 mm or more, and particularly preferably 0.6 mm or more.

In addition, regarding the shape of the concave deformation portion, the cross-sectional outline can be made into an arc shape, a parabola shape, a cone shape, or a dish shape. However, in order to effectively suppress the amount of bending, the cross-sectional profile of the concave deformation portion is preferably parabolic. In addition, by relaxing the boundary portion between the outer peripheral flat portion and the curved portion (making the curvature radius R larger), it is possible to suppress the occurrence of cracks when bonded to the silicon substrate.

In addition, when the substrate is temporarily fixed before bonding, the bending amount of the concave deformation portion is preferably 2.5 mm or less. This can suppress operating problems in the bonding device and easily prevent damage during bonding. From this point of view, the curvature of the concave deformation portion is preferably 2.0 mm or less, and more preferably 1.0 mm or less.

At this time, if the thickness variation (so-called TTV) of the entire temporarily fixed substrate is large, thickness variation occurs in the adhesive layer during bonding with the silicon substrate or electronic component wafer, which may cause deformation after bonding. Therefore, the thickness variation is 10um or less is preferred. In addition, when forming high-precision wiring on a silicon substrate or electronic component to be bonded, the thickness variation is preferably 5 um or less, and more preferably 3 um or less.

In addition, the bending amount of the concave deformation part is measured as follows. That is, the virtual surface L is obtained by extending the fixed surface (flat surface) of the outer peripheral flat plate portion onto the concave deformation portion. Then, the depth of the deepest portion among the concave deformation portions is defined as the bending amount W when viewed from the virtual plane L. In addition, as a specific measuring device, a laser length measuring machine can be used to measure the shape of a substrate placed on a flat table.

The planar shapes and planar dimensions of the temporarily fixed substrate, the silicon substrate, etc. are not particularly limited. The temporarily fixed substrate and the silicon substrate may have the same planar shape and planar dimensions, or they may have different planar shapes and planar dimensions. Specifically, for example, the temporarily fixed substrate, the silicon substrate, etc. may each have a disc shape, a rectangular shape, an oval shape, an elliptical shape, a triangular shape, or a polygonal shape. Among them, in particular, when the temporarily fixed substrate and the silicon substrate are respectively in a disc shape or a regular polygonal shape, point symmetry is preferred, and a disc shape is more preferred. At this time, thermal shrinkage occurs equally in all directions with the point symmetry axis as the center.

Furthermore, when the temporary fixed substrate, silicon substrate, etc. is in the shape of a disk, the diameter (width) is preferably 100 to 300 mm. When an orientation plane or notch is formed on the silicon substrate, the same orientation plane or notch can also be formed on the temporarily fixed substrate, so that it is easy to position during bonding and can reduce bonding misalignment. In addition, when the temporary fixed substrate or silicon substrate is square or rectangular, the length of one side is preferably 100 to 1000 mm. At this time, it is preferable from the viewpoint of suppressing the amount of bending after bonding that the corner portion has an R or C shape.

Temporarily fix the thickness of the substrate, for example, 0.2~5.0mm is preferred, and 0.5~2.0mm is more preferred. By making this 0.2 mm or more, it becomes easy to suppress bending after bonding, and it becomes easy to prevent damage to the temporarily fixed substrate. In addition, by making it 5.0 mm or less, the weight of the substrate can be suppressed and transportation becomes easier.

When joining a temporarily fixed substrate and a silicon substrate or the like using a thermosetting resin, the temporarily fixed substrate and the silicon substrate or the like are overlapped and fixed under pressure, and then are heated to harden the thermosetting adhesive to obtain a bonded body.

As an adhesive for temporarily fixing the substrate and the silicon substrate, etc., in addition to the thermosetting resin, UV (ultraviolet curing type) adhesive, double-sided tape, hot melt adhesive, etc. can be exemplified. In addition, as a method of providing the adhesive on the temporarily fixed substrate, various methods such as roller coating, spray coating, screen printing, and spin coating can be used.

In addition, it is preferable to form a peeling layer between the adhesive layer and the temporarily fixed substrate. As such a peeling layer, a laser peeling type in which the peeling layer is carbonized and peeled off by irradiation of laser light, and a UV peeling type in which it is deactivated by irradiation of UV light and loses its adhesiveness and peels off, can also be used. Thermal peeling type uses heat to cause the components in the layer to bubble and peel off.

Various electronic component structures can be produced on the silicon substrate of the present invention. For example, when manufacturing a CCD or CMOS, a silicon substrate is bonded to a temporarily fixed substrate, the silicon substrate is thinned, and then a wiring layer is formed by performing a thin film forming step and a pattern forming step. At this time, if the bonding body between the temporarily fixed substrate and the silicon substrate is greatly bent, it will be difficult to pattern the fine wiring structure with high precision in the patterning step, so the present invention is particularly useful.

In addition, electronic component wafers can be provided on the silicon substrate, and each electronic component wafer can be electrically connected to the wiring layer. Then, after the silicon substrate is separated from the temporarily fixed substrate, each electronic component wafer can be separated by cutting the silicon substrate.

In addition, the present invention can be favorably used in so-called FOWLP technology. In FOWLP technology, the electronic component wafer is temporarily placed on a supporting substrate (temporarily fixed substrate), and after being sealed with a resin mold, wiring is formed on the surface of the resin mold, and then the electronic component wafer and mold resin are removed from the supporting substrate (temporarily fixed substrate). The substrate) is peeled off to achieve a thin structure. Then, after separating the resin mold and the sealed electronic component wafer from the temporarily fixed substrate, the resin mold is cut, and each electronic component wafer can be separated separately. In this case, when the electronic component wafer is resin-sealed and wiring is formed on the temporarily fixed substrate, the bending of the bonded body due to the difference in thermal expansion of each component becomes a problem, but this can be improved by using the present invention. .

In addition, when the area of the electronic component to which the substrate is temporarily fixed is enlarged, warping of the bonded body caused by the thermal expansion difference between the temporarily fixed substrate and the electronic component wafer becomes a problem, but this can be improved by using the present invention. In particular, if the electronic component wafer occupies more than 60% of the area of the temporarily fixed substrate, this tendency will be significant, so the present invention is very useful.

When the substrate is temporarily fixed to form the outer peripheral flat plate portion and the concave deformation portion, a jig having a flat portion suitable for the outer peripheral flat plate portion and a protrusion suitable for the concave deformation portion is prepared, and the substrate is temporarily fixed by heating. The charge causes it to plastically deform. Alternatively, the flat plate is accommodated in a metal mold having the same flat portion and protrusions, and the outer peripheral flat plate portion and the concave deformation portion can be formed by heating and pressing the metal mold.

When thinning the silicon substrate through processing, a grinder can be used. That is, the temporarily fixed substrate side of the bonded body between the temporarily fixed substrate and the silicon substrate is fixed using a vacuum suction cup or the like, and the silicon substrate side is processed with grinding abrasive grains to obtain a desired thickness. [Example]

(Examples 1 to 7) A slurry was prepared by mixing the following components. (raw material powder) ‧α-alumina powder with purity of 99.99% 100 parts by mass ‧MgO (magnesium oxide) 250ppm ‧ZrO ₂ (zirconia) 400ppm ‧Y ₂ O ₃ (yttrium trioxide) 15ppm (dispersant) ‧2 -Ethylhexanol 45 parts by mass (binder) ‧PVB resin 4 parts by mass (dispersant) ‧Polymer surfactant 3 parts by mass (plasticizer) ‧DOP 0.1 parts by mass

The slurry was formed into a thin strip with a thickness of 0.7 mm after firing using the doctor blade method, and cut into a size of ψ300 mm after firing. After the obtained powder compact was fired (preparatory firing) at 1240°C in the air, the substrate was placed on a molybdenum plate and held at 1800°C for 2.5 hours in an atmosphere of hydrogen 3:nitrogen 1. Fired. After that, grinding with a grinder, fine grinding with diamond abrasive grains, and grinding with CMP liquid were performed in sequence to obtain a temporarily fixed substrate material 20 with a thickness of 0.6 mm (Fig. 5(a)).

Next, the material 20 is clamped with a jig of a predetermined shape and deformed by heat treatment at a temperature of 1600° C. to obtain a temporarily fixed substrate 21 (see FIGS. 5(b) and (c) ).

The obtained temporarily fixed substrate and a silicon substrate of the same diameter were bonded with a thermosetting resin, and the presence or absence of cracks at this time and the amount of bending after bonding were measured. However, the peeling layer uses a heat peeling adhesive. Next, the silicon substrate was ground to a thickness of 0.1 mm, and the amount of bending of the ground bonded body was measured.

However, by changing the molding conditions or the shape of the jig, the diameter (width) of the temporarily fixed substrate, the width of the outer peripheral flat plate portion, and the amount of bending W were variously changed as shown in Table 1.

Then, for each example, the presence or absence of cracks during bonding (visual inspection), the amount of bending of the bonded body after bonding, and the amount of curvature of the bonded body after grinding the silicon substrate were measured. The measurement results are shown in Table 1.

Table 1 Example 1 2 3 4 5 6 7 Temporarily fixed substrate width R (mm) 300 300 300 300 300 300 200 Width of outer peripheral flat plate F/2 (mm) 5 25 90 5 25 90 15 R/F(%) 3.3 17 60 3.3 17 60 15 Bending amount of concave deformation part (mm) -0.5 -0.5 -0.5 -0.8 -0.8 -0.8 -0.8 subsequent cracks without without without without without without without The amount of bending of the bonded body immediately after joining (mm) +1.3 +1.1 +1.2 +0.7 +0.6 +0.9 +0.1 Bending amount of silicon substrate after grinding (mm) +1.0 +0.9 +0.8 +0.5 +0.4 +0.5 +0.1

(Comparative Examples 1~3) The same experiment as Example 1 was performed. However, in this example, the shape of the jig during heat treatment is adjusted, and the outer peripheral flat plate portion is not provided on the temporarily fixed substrate. In addition, by changing the molding conditions or the shape of the jig, the diameter ψ and the bending amount W of the temporarily fixed substrate were variously changed as shown in Table 2. The width of the outer peripheral flat plate portion is 0 mm.

Then, for each example, the presence or absence of cracks during bonding (visual inspection), the amount of bending of the bonded body after bonding, and the amount of curvature of the bonded body after grinding the silicon substrate were measured. The measurement results are shown in Table 2.

Table 2 Example 1 2 3 Temporarily fixed substrate width R (mm) 300 300 300 Width of outer peripheral flat plate F/2 (mm) 0 0 0 R/F(%) 0 0 0 Bending amount of concave deformation part (mm) -0.5 -0.8 -0.8 subsequent cracks without without without The amount of bending of the bonded body immediately after joining (mm) +1.9 +1.8 +0.8 Bending amount of silicon substrate after grinding (mm) +1.2 +1.0 +0.3

When the temporarily fixed substrate of the comparative example without the outer peripheral flat plate portion is used, the bending amount of the bonded body becomes relatively large, and the bending amount of the silicon substrate after polishing also becomes large.

When the temporarily fixed substrate of the present invention is used, even if the amount of bending of the temporarily fixed substrate is the same as that of the comparative example, the amount of bending of the bonded body becomes smaller. In addition, by setting the width ratio of the outer peripheral flat plate portion to 4 to 60%, the effect of the present invention becomes more significant.

In addition, each temporarily fixed substrate of Examples 1 to 7 was produced, the electronic component wafer was bonded, and sealed with a resin mold. Otherwise, the electronic component wafer and the resin mold were separated from the temporarily fixed substrate in the same manner as in Examples 1 to 7. Then, the resin mold is cut to obtain each electronic component wafer. The presence or absence of cracks during bonding (visual observation) and the amount of bending of the bonded body after bonding were measured, and the same results as in Examples 1 to 7 were obtained.

1: Temporarily fix the substrate 1a: Fixed surface 13:Jig 15:Jig 15a:Flat surface 20: Temporarily fix the substrate material 20a, 20b: Main side 21a, 21b: Main side 21: Temporarily fix the substrate 21A: Temporarily fix the substrate 21c: Peripheral flat plate part 21d: Concave deformation part 21e:Flat surface 22:Silicon substrate 22B: Silicon layer 22A:Silicon substrate 23:Follow the body 23A:Adhering body 34: Next layer 35:Resin mold 35b: Resin filling the gap 37 of the electronic component 36: Electronic components 37: Gap L: virtual surface W: bending amount R: wide

[Fig. 1] (a) shows the silicon-based sheet 2 and the temporarily fixed substrate 1 before bonding; (b) shows a bonded body that joins the substrate 2 and the temporarily fixed substrate 1; (c) shows a state in which the silicon layer 2A of the bonded body is thinned. [Figure 2] (a) shows the state where the wiring 6 is provided on the silicon layer 2A; (b) shows the state where the silicon substrate is separated from the temporarily fixed substrate 1 . [Figure 3] (a) is a schematic diagram showing the silicon substrate 12 and the curved temporarily fixed substrate 11 (before bonding); (b) shows the state in which the silicon substrate 12 and the temporarily fixed substrate 11 are joined; (c) shows the bonded body 14 . [Figure 4] (a) shows a state in which the silicon layer 14A of the bonded body is thinned; (b) shows a bonded body between the silicon layer 14A and the temporarily fixed substrate 11A; (c) shows a state in which the silicon layer 12B is separated from the temporarily fixed substrate 11A. . [Figure 5] (a) represents the material before processing 20; (b) shows the temporarily fixed substrate 21 according to the embodiment of the present invention; (c) is a plan view of the temporarily fixed substrate 21. [Figure 6] (a) is a schematic diagram showing the silicon substrate 22 and the temporarily fixed substrate 21 (before bonding); (b) shows the state in which the silicon substrate 22 and the temporarily fixed substrate 21 are joined; (c) shows the bonded body 23 . [Figure 7] (a) shows the state in which the silicon substrate 22B of the bonded body is thinned; (b) shows the bonded body of the silicon substrate 22B and the temporarily fixed substrate 21A; (c) shows the state in which the silicon substrate 22B is separated from the temporarily fixed substrate 21 . [Figure 8] FIG. 8 is a schematic diagram showing the rectangular temporarily fixed substrate 31 in plan view. [Figure 9] (a) shows the state in which the electronic component wafer 36 is temporarily fixed with the resin mold 35; (b) shows the state in which the electronic component 36 and the resin mold 35 are separated from the temporarily fixed substrate 1 by light irradiation.

F/2: Width of outer peripheral flat plate part

L: virtual surface

R: wide

W: bending amount

t21: Temporarily fix the thickness of the substrate

20: Temporarily fix the substrate material

20a, 20b: Main side

21: Temporarily fix the substrate

21a, 21b: Main side

21c: Peripheral flat plate part

21d: Concave deformation part

21e:Flat surface

Claims (13)

A temporarily fixed substrate made of ceramic or glass and provided with: a fixed surface for joining at least one of a silicon substrate and an electronic component wafer; and a bottom surface on the opposite side of the fixed surface, characterized by: : It has: an outer peripheral flat plate portion; and a concave deformation portion surrounded by the outer peripheral flat plate portion, the fixing surface is a flat surface on the outer peripheral flat plate portion, and the fixing surface is recessed from the flat surface on the concave deformation portion. The temporarily fixed substrate as described in item 1 of the patent application, wherein the ceramic is translucent alumina. The temporarily fixed substrate as described in claim 1 or 2, wherein the width of the outer peripheral flat plate portion is 4 to 60% of the width of the temporarily fixed substrate. The temporarily fixed substrate as described in any one of items 1 or 2 of the patent application, wherein the bending amount of the concave deformation portion is 0.1~2.5mm. A temporary fixing method, characterized by: having the above-mentioned fixing surface for temporarily fixing the substrate according to any one of claims 1 to 4, and obtaining a bonded body by following at least one of the above-mentioned silicon substrate and the above-mentioned electronic component wafer. steps. The temporary fixing method described in Item 5 of the patent application includes: processing the silicon substrate of the bonded body to thin the silicon substrate to form a silicon layer; and separating the silicon layer from the temporarily fixed substrate. steps. The temporary fixing method described in item 6 of the patent application includes the step of arranging an electronic component structure on the silicon layer. The temporary fixing method described in claim 5 includes the step of covering the electronic component wafer with a resin mold after bonding the electronic component wafer to the fixing surface of the temporarily fixing substrate. A manufacturing method of electronic components, characterized by: having: The step of bonding the above-mentioned fixed surface of the temporarily fixed substrate according to any one of the patent claims 1 to 4 to the above-mentioned silicon substrate to obtain an adhesive body; disposing electrons in the silicon layer of the above-mentioned silicon substrate or on the above-mentioned silicon layer The step of building the wafer; and the step of separating the silicon layer and the electronic component wafer from the temporarily fixed substrate. The manufacturing method of an electronic component according to claim 9 includes the step of dividing the silicon layer after separating the silicon layer from the temporarily fixed substrate. The method for manufacturing an electronic component as described in claim 9 or 10 includes the step of arranging wiring in the silicon layer and connecting the wiring to a wafer having the electronic component. A manufacturing method of electronic components, characterized by: having the steps of: bonding the electronic component wafer to the above-mentioned fixing surface of the temporarily fixed substrate described in any one of items 1 to 4 of the patent application scope to obtain a bonded body; and attaching the above-mentioned A step of separating the electronic component wafer from the temporarily fixed substrate. The method for manufacturing an electronic component according to claim 12 includes the step of covering the electronic component wafer with a resin mold after bonding the electronic component wafer to the fixing surface of the temporarily fixed substrate.

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